Final answer:
In the book "Rain Reign", Rose's father is supposed to go to Hartford Elementary to discuss her.
Step-by-step explanation:
In the book "Rain Reign", Rose's father is supposed to go to Hartford Elementary to discuss her on the day the question is being asked. This information is mentioned in the text when Harry asks Rose about her father and his daughter who are due to arrive that day. So, it can be inferred that Rose's father is supposed to go to Hartford Elementary to discuss her on that specific day.